Mercury,selenium, PCBs and fatty acids in fresh and canned fish available on the Slovenian market

In order to contribute to the general understanding of the risks and benefits of consuming fish and fish products, total mercury (THg), monomethylmercury (MeHg), polychlorinated biphenyls (PCBs), selenium (Se), n-3 and n-6 fatty acids were determined in fresh and canned fish on the Slovenian market. Furthermore, the mercury exposure of pregnant women in Slovenia was assessed by determining total mercury (THg) in hair, and through fresh and canned fish consumption obtained by a food frequency questionnaire. Based on the frequency of fish consumption and levels of MeHg, THg and PCBs determined in the present study, it can be concluded that fish available on the Slovenian market do not represent a health risk. It was also confirmed that fish are important sources of selenium and n-3 fatty acids.     

Fatty acid composition of eggs produced by the Slovenian autochthonous Styrian hen

The fatty acid composition of eggs produced by the autochthonous Styrian hen reared in two rearing systems was determined. Eggs were collected four times during the year. The fatty acid composition was determined by the in situ transesterification method and gas chromatography–flame ionisation detection (GC–FID). Eggs of the Styrian hen from free range contained significantly more α-linolenic, eicosapentaenoic (EPA), docosapentaenoic (DPA) and docosahexaenoic acid (DHA), as well as more total n−3 fatty acids. On the other hand, eggs from caged hens contained significantly more linoleic, arachidonic, as well as total polyunsaturated fatty acids (PUFA) and n−6 PUFA. The n−6/n−3 ratio was better from the nutritional point of view in eggs from free range. The fatty acid content is expressed in wt.%, as well as mg/100 g of yolk and mg/100 g of fresh egg, to better understand how much each of fatty acid is consumed with an edible portion.     

Determination of ultratrace levels of selenium in fruit and vegetable samples grown and consumed in Portugal

The selenium content in fruit and vegetable samples from two regions in Portugal were analysed using hydride generation atomic fluorescence spectrometry (HG-AFS) and radiochemical nuclear activation analysis (RNAA) – two analytical methods with very low limits of detection. The lower detection limits of HG-AFS, 3 μg kg⁻¹ and 8 μg kg⁻¹ (according to conditions used for digestion), and for RNAA, 10 μg kg⁻¹, meant that it was possible to determine selenium in samples previously analysed using the replicate sample instrumental nuclear activation analysis (RSINAA) with a higher detection limit associated.     

Enhanced selenium content in buckwheat (<Emphasis Type="Italic">Fagopyrum esculentum</Emphasis> Moench) and pumpkin (<Emphasis Type="Italic">Cucurbita pepo</Emphasis> L.) seeds by foliar fertilisation

The fruit and thin-husked seeds of the pumpkin (Cucurbita pepo L.) and buckwheat grain (Fagopyrum esculentum Moench), both grown in Slovenia, were analysed for selenium (Se) content following foliar application of Se(VI) solution during the period of blooming. Samples were digested by a H₂SO₄-HNO₃-H₂O₂-V₂O₅ mixture and Se determined, based on hydride generation atomic fluorescence spectrometry. The whole procedure from weighing to measuring was carried out in the same Teflon vessel. The detection limit of the method was 0.14 ng g^–1 solution. Buckwheat seeds from untreated plants contained 47 ng g^–1 of Se and 394 ng g^–1 from plants after foliar fertilisation with Se. Pumpkin seeds from untreated plants contained 108 ng g^–1 of Se, and 381 ng g^–1 of Se from Se-treated plants, all per lyophilised sample. Se content in lyophilised pumpkin fruit was 15 ng g^–1 in untreated plants and 20 ng g^–1 in Se-treated pumpkin plants. It is thus feasible to enhance Se content in buckwheat and pumpkin seeds by foliar fertilisation, making them a rich source of dietary Se and useful as a raw material for enriched food products.     

An influence of cooking on fatty acid composition in three varieties of common beans and in lentil

The fatty acid composition of three raw and cooked freeze-dried common bean varieties (Phaseolus vulgaris), namely enjevec, Semenarna 22 and Cipro, and of the lentil (Lens esculenta), var. Anicia, was determined and the influence of storage on their composition was studied. Analyses of fatty acid composition were conducted by in situ transesterification and capillary column gas-liquid chromatography. In raw milled beans average values of about 16% saturated fatty acids (SAT), 6% monosaturated fatty acids (MUFA) and 78% polyunsaturated fatty acids (PUFA) were found. Somewhat different values of 15% of SAT, 25% MUFA and 60% PUFA were found in lentil. In cooked beans the content of all fatty acids was slightly decreased. In cooked lentil the decrease was almost 50%, but the ratios of SAT, MUFA and PUFA in both cases were practically the same. After two years of storage at 4 °C the fatty acid content in raw milled beans was unchanged, but altered in cooked ones. The amounts of linoleic (18:2, n-6) and -linolenic (18:3, n-3) acid decreased, but myristic (14:0), margaric (17:0) and arachidic (20:0) acids increased. It was found that freeze-dried cooked beans, prepared from raw seed beans, kept 2.5 years at 10 °C, have practically the same fatty acid composition as freeze-dried cooked beans 0.5 year after harvesting.     

Applicability of neutron activation analysis (NAA) in quantitative determination of some essential and toxic trace elements in food articles

Accurate and reliable data on microgram and nanogram quantities of some essential and toxic elements in most food articles are very scarce. Neutron activation analysis (NAA), with its essentially blankfree advantage, is a valuable approach in the field of determination of trace elements in different foodstuffs and diets. Accordingly, various radiochemical (RNAA) and instrumental (INAA) approaches have been developed in our laboratory for the elements As, Cd, Co, Cu, Hg, I, Mo, Ni, Sb, Se, Sn, Th, U, V, and others, and verified by the analysis of compositionally appropriate certified reference materials.This communication was presented as a poster at EURO FOOD CHEM VIII, Vienna, September 18–20, 1995, and was one of three such posters which were awarded as being outstanding     

Determination of macronutrients and some essential elements in the slovene military diet

The energy and nutrient values for military nutrition are defined in the nutritional recommendations of the Slovene Armed Forces. In this study 35 daily military diets sampled in the years 2002 and 2005 by the double basket method were analysed, for energy, total fat, protein, dietary fibre and the elements Ca, Mg, Na, P, K, Fe, Zn, Cu, I and Se. The daily diets were collected at different locations in Slovenia. The aim was to establish whether energy value, content of fat, protein, dietary fibre and selected essential elements are in compliance with the nutritional recommendations of the Slovene Armed Forces. The results indicate that daily intake of essential elements from military meals was sufficient, with the exception of Ca and Zn in diets sampled in 2005. The study was the first in Slovenia analysing daily intakes of essential elements in an adult population aged 19–27 years.     

Distribution of selenium and phenolics in buckwheat plants grown from seeds soaked in Se solution and under different levels of UV-B radiation

Seeds of common buckwheat (Fagopyrum esculentum) were soaked in water, sodium selenate (5, 10 or 20 mg Se^VI/L), or sodium selenite (10 or 20 mg Se^IV/L) solutions. Plants grown from soaked seeds were exposed to reduced UV-B radiation, ambient, or enhanced UV-B. The mass fraction of selenium in leaves was much higher in plants obtained from seeds soaked with selenate (up to 185 ng/g) in comparison to selenite (up to 103 ng/g). In plants obtained from seeds soaked in water, regardless of UV-B levels, the highest concentration of selenium was found in leaves, where the values were between 45 and 66 ng Se/g. In buckwheat leaves 44.5–63.6 mg/100 g d.m. of fagopyrin was found, and in stems 14.3–26.4 mg/100 g d.m.; here no influence of seed soaking solution or UV-B exposure was found. The content of total flavonoids in leaves was 7.8–15.9% and in stems 1.4–4.1%.     

Selenium species in buckwheat cultivated with foliar addition of Se(VI) and various levels of UV-B radiation

Common (Fagopyrum esculentum Moench) and tartary (Fagopyrum tataricum Gaertn.) buckwheat was treated by spraying the leaves with a water solution containing 15 mg Se per litre in the form of sodium selenate in the flowering period. The selenium content in all parts of plant was found to be less than 200 ng g⁻¹ in non-treated and in the range 2700–4650 ng g⁻¹ in selenium treated buckwheat. Exposure to UV-B radiation lead to higher Se accumulation in flowers of both Se enriched cultivars. For speciation analysis enzymatic hydrolysis was carried out, separation and detection of selenium species was performed by high performance liquid chromatography–ultraviolet treatment–hydride generation atomic fluorescence spectrometry (HPLC–UV–HG-AFS). In flowers and leaves, on average 11% of the Se content was soluble and in the form of Se(VI), representing between 0.6% (flowers) and 3% (leaves) of the Se content. The remaining soluble non-amino acid organic Se was not detected by HPLC–UV–HG-AFS. In seeds 93% of the selenium content was found in the extracts and the main selenium species was SeMet with 93 ± 5% relative to the selenium content.     

The Slovenian food composition database

The preliminary Slovenian food composition database was created in 2003, through the application of the Data management and Alimenta nutritional software. In the subsequent projects, data on the composition of meat and meat products of Slovenian origin were gathered from analyses, and low-quality data of the preliminary database were discarded. The first volume of the Slovenian food composition database was published in 2006, in both electronic and paper versions. When Slovenia joined the EuroFIR NoE, the LanguaL indexing system was adopted. The Optijed nutritional software was developed, and later upgraded to the OPEN platform. This platform serves as an electronic database that currently comprises 620 foods, and as the Slovenian node in the EuroFIR virtual information platform. With the assimilation of the data on the compositions of foods of plant origin obtained within the latest project, the Slovenian database provides a good source for food compositional values of consistent and compatible quality.